WinLTP is a Windows data acquisition program designed for the investigation of long-term potentiation (LTP), long-term depression (LTD), and synaptic responses in general. The capabilities required for basic LTP and LTD experiments include alternating two-input extracellular pathway stimulation, LTP induction by single train, theta burst, and primed burst stimulation, and LTD induction by low frequency stimulation. WinLTP provides on-line analyses of synaptic waveforms including measurement of slope, peak amplitude, population-spike amplitude, average amplitude, area, rise time, decay time, duration, cell input resistance, and series resistance. WinLTP also has many advanced capabilities that extend beyond basic LTP experimental capabilities: (1) analysis of all the evoked synaptic potentials individually within a sweep, and the analysis of the entire train-evoked synaptic response as a single entity. (2) Multitasking can be used to run a Continuous Acquisition task (saving data to a gap-free Axon Binary File), while concurrently running the Stimulation/Acquisition Sweeps task. (3) Dynamic Protocol Scripting can be used to make more complicated protocols involving nested Loops (with counters), Delays, Sweeps (with various stimulations), and Run functions (which execute a block of functions). Protocol flow can be changed while the experiment is running. WinLTP runs on National Instruments M-Series and Molecular Devices Digidata 132x boards, and is available at www.winltp.com.